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		<title>three.js webgpu - bpcem</title>
		<meta charset="utf-8">
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		<link type="text/css" rel="stylesheet" href="example.css">
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		<div id="info">
			<a href="https://threejs.org/" target="_blank" rel="noopener" class="logo-link"></a>

			<div class="title-wrapper">
				<a href="https://threejs.org/" target="_blank" rel="noopener">three.js</a><span>BPCEM</span>
			</div>

			<small>
				Box projected cube environment mapping (BPCEM).
			</small>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';
			import { bumpMap, float, getParallaxCorrectNormal, pmremTexture, reflectVector, texture, uniform, vec3 } from 'three/tsl';

			import { Inspector } from 'three/addons/inspector/Inspector.js';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
			import { RectAreaLightHelper } from 'three/addons/helpers/RectAreaLightHelper.js';
			import { RectAreaLightTexturesLib } from 'three/addons/lights/RectAreaLightTexturesLib.js';

			let camera, scene, renderer;

			let controls, cubeCamera;

			let groundPlane, wallMat;

			init();

			async function init() {

				THREE.RectAreaLightNode.setLTC( RectAreaLightTexturesLib.init() );

				// scene
			
				scene = new THREE.Scene();

				// camera

				camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 0.1, 1000 );
				camera.position.set( 0, 200, - 200 );

				// cube camera for environment map

				const renderTarget = new THREE.WebGLCubeRenderTarget( 512 );
				renderTarget.texture.type = THREE.HalfFloatType;
				renderTarget.texture.minFilter = THREE.LinearMipmapLinearFilter;
				renderTarget.texture.magFilter = THREE.LinearFilter;
				renderTarget.texture.generateMipmaps = true;
				renderTarget.texture.mapping = THREE.CubeReflectionMapping;

				cubeCamera = new THREE.CubeCamera( 1, 1000, renderTarget );
				cubeCamera.position.set( 0, - 100, 0 );

				// ground floor ( with box projected environment mapping )
			
				const loader = new THREE.TextureLoader();
				const rMap = loader.load( 'textures/lava/lavatile.jpg' );
				rMap.wrapS = THREE.RepeatWrapping;
				rMap.wrapT = THREE.RepeatWrapping;
				rMap.repeat.set( 2, 1 );

				const roughnessUniform = uniform( 0.25 );

				const defaultMat = new THREE.MeshStandardNodeMaterial();
				defaultMat.envNode = pmremTexture( renderTarget.texture );
				defaultMat.roughnessNode = texture( rMap ).mul( roughnessUniform );
				defaultMat.metalnessNode = float( 1 );

				const boxProjectedMat = new THREE.MeshStandardNodeMaterial();
				boxProjectedMat.envNode = pmremTexture( renderTarget.texture, getParallaxCorrectNormal( reflectVector, vec3( 200, 100, 100 ), vec3( 0, - 50, 0 ) ) );
				boxProjectedMat.roughnessNode = texture( rMap ).mul( roughnessUniform );
				boxProjectedMat.metalnessNode = float( 1 );

				groundPlane = new THREE.Mesh( new THREE.PlaneGeometry( 200, 100, 100 ), boxProjectedMat );
				groundPlane.rotateX( - Math.PI / 2 );
				groundPlane.position.set( 0, - 49, 0 );
				scene.add( groundPlane );

				// walls
			
				const [ diffuseTex, bumpTex ] = await Promise.all( [
					loader.loadAsync( 'textures/brick_diffuse.jpg' ),
					loader.loadAsync( 'textures/brick_bump.jpg' )
				] );
				diffuseTex.colorSpace = THREE.SRGBColorSpace;

				wallMat = new THREE.MeshStandardNodeMaterial();

				wallMat.colorNode = texture( diffuseTex );
				wallMat.normalNode = bumpMap( texture( bumpTex ), float( 5 ) );

				const planeGeo = new THREE.PlaneGeometry( 100, 100 );

				const planeBack1 = new THREE.Mesh( planeGeo, wallMat );
				planeBack1.position.z = - 50;
				planeBack1.position.x = - 50;
				scene.add( planeBack1 );

				const planeBack2 = new THREE.Mesh( planeGeo, wallMat );
				planeBack2.position.z = - 50;
				planeBack2.position.x = 50;
				scene.add( planeBack2 );

				const planeFront1 = new THREE.Mesh( planeGeo, wallMat );
				planeFront1.position.z = 50;
				planeFront1.position.x = - 50;
				planeFront1.rotateY( Math.PI );
				scene.add( planeFront1 );

				const planeFront2 = new THREE.Mesh( planeGeo, wallMat );
				planeFront2.position.z = 50;
				planeFront2.position.x = 50;
				planeFront2.rotateY( Math.PI );
				scene.add( planeFront2 );

				const planeRight = new THREE.Mesh( planeGeo, wallMat );
				planeRight.position.x = 100;
				planeRight.rotateY( - Math.PI / 2 );
				scene.add( planeRight );

				const planeLeft = new THREE.Mesh( planeGeo, wallMat );
				planeLeft.position.x = - 100;
				planeLeft.rotateY( Math.PI / 2 );
				scene.add( planeLeft );

				// area lights

				const width = 50;
				const height = 50;
				const intensity = 5;
			
				const blueRectLight = new THREE.RectAreaLight( 0x9aaeff, intensity, width, height );
				blueRectLight.position.set( - 99, 5, 0 );
				blueRectLight.lookAt( 0, 5, 0 );
				scene.add( blueRectLight );

				const blueRectLightHelper = new RectAreaLightHelper( blueRectLight, 0xffffff );
				blueRectLight.add( blueRectLightHelper );

				const redRectLight = new THREE.RectAreaLight( 0xf3aaaa, intensity, width, height );
				redRectLight.position.set( 99, 5, 0 );
				redRectLight.lookAt( 0, 5, 0 );
				scene.add( redRectLight );

				const redRectLightHelper = new RectAreaLightHelper( redRectLight, 0xffffff );
				redRectLight.add( redRectLightHelper );

				// renderer

				renderer = new THREE.WebGPURenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				renderer.inspector = new Inspector();
				document.body.appendChild( renderer.domElement );

				await renderer.init();

				updateCubeMap();

				window.addEventListener( 'resize', onWindowResize );

				// controls

				controls = new OrbitControls( camera, renderer.domElement );
				controls.target.set( 0, - 10, 0 );
				controls.maxDistance = 400;
				controls.minDistance = 10;
				controls.update();

				// gui

				const gui = renderer.inspector.createParameters( 'Parameters' );
				const params = {
					'box projected': true
				};
				gui.add( params, 'box projected' ).onChange( ( value ) => {

					groundPlane.material = ( value ) ? boxProjectedMat : defaultMat;

				} );
				gui.add( roughnessUniform, 'value', 0, 1 ).name( 'roughness' );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function updateCubeMap() {

				groundPlane.visible = false;

				cubeCamera.position.copy( groundPlane.position );

				cubeCamera.update( renderer, scene );

				groundPlane.visible = true;

			}

			function animate() {

				renderer.render( scene, camera );

			}

		</script>

	</body>
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